Silver halide material for optical memory devices with luminescent reading and methods for the treatment thereof

ABSTRACT

This invention concerns a luminescent optical memory material and method of forming this material, including the encoding of information by a photographic process. The method involves the use of silver halide crystals of a defined size range, with the optional use of sensitizers, emulsion stabilizers, and other agents followed by the absorption of luminescent dyes on the developed silver particle to form a luminescent optical memory system. The method involves synthesis of a photographic emulsion with silver halide crystals of a defined size range, applying photographic emulsion to a substrate, exposing to light photochemical treatment and a process of transformation of the silver particles formed in the places exposed by light into luminescent particles. The method involves obtaining a multi-layer luminescent material for a three-dimensional optical memory devices.

This application is a continuation of application Ser. No. 09/028,932,filed Feb. 24, 1998, now U.S. Pat. No. 6,265,140, which claims thebenefit of U.S. application 60/038,918 filed Feb. 24, 1997 and hereinincorporates by reference that application for all purposes.

FIELD OF THE INVENTION

The present invention is directed to the field of materials for opticalrecording, storing and reading of information, including systems for 3-Doptical memory based on luminescent compounds which can be used withCD-ROM systems.

The next generation of computer memories will be connected with memorysystems using super dense optical memory materials to take advantage ofthese materials memory storage density and access speed. The opticaldisks of CD-ROM's are examples of optical memory systems.

The disadvantages of current CD-ROM's are an insufficient density ofmemory, insufficient amount of memory and unfavorable ratio ofsignal-to-noise for the next generation of computers.

Presently, some new materials, including the materials of the inventionwith luminescent properties for the reading of information, have beensuggested for the improved optical memory systems that are underdevelopment. Such materials have an increased recording density, a highsignal-to-noise ratio, and increased stability during storage andutilization.

BACKGROUND OF THE INVENTION

There are different prior art systems for optical recording based on theforming of fluorescent compounds from non-fluorescent precursors,including the UV-light exposed compounds ofbis-diarylchloromethyl-1,3,4-oxadiazoles which are disclosed in U.S.Pat. No. 3,869,363. Moreover, many other systems are described in Zweig“Photochemical Generation of Stable Fluorescent Compounds” in Pure andApplied Chemistry, Vol. 33, 389-410 (1973) herein incorporated byreference. The main disadvantage of systems using these compounds is therequirement to use lasers with wavelengths shorter than 500 nm for thereading of stored information in the system. Thus, these systems excludethe possible use of modern diode lasers with wavelengths over 600 nm forreading the information in the storage device.

Photochromic lactams of Rhodamine B and peri-phenoxy derivatives ofpolycyclic p-quinones are suggested for use in these memory devices inwhich the luminophores are photochemically generated (U.S. ProvisionalPatent Application No. 60/03258 filed on Dec. 10, 1996 and U.S.Provisional Patent Application No. 60/033709 filed on Dec. 20, 1996,herein incorporated by reference). These compounds can be used inoptical memory devices employing modem diode lasers with the wavelengthsover 600 nm for reading the stored information. However, photochromicsystems based on the generation of luminescent products have the commondisadvantage of the destruction of the photoinduced luminescent productduring the reading process. Moreover, these systems have low lightsensitivities which then requires high energy densities of irradiationduring the recording process which can lead to destruction of the memorymaterial.

SUMMARY OF THE INVENTION

This invention provides for a super dense optical memory material forinformation storage and use with computers. The invention includes theformation of silver halide crystals of a defined size and the optionaltreatment of these silver halide crystals with sensitizers and/orspectral sensitizers. The silver halide crystals of the invention arethen exposed to light, developed and fixed. The silver grains can thenbe treated with luminescent dyes to form the luminescent particles ofthe invention. Alternatively, the silver particles or the surface of thesilver particles can be oxidized and luminescent dyes sorbed onto theoxidized surface or the oxidized particles can be treated to forminsoluble salts which are then treated with luminescent dyes to form theluminescent particles of the invention. In addition, polyvalent cationscan be sorbed onto the surface of the silver particles, the oxidizedsilver particles, the silver salts or the insoluble salts to formlumincent metal complex compounds. In addition, mercapto- orbenzotriazoyl compounds can be used to promote the adsorption of theluminescent dyes onto the silver or other insoluble particles.

The optical memory material of the invention can be formed either into asingle layer of polymer with silver halide crystals or a threedimensional memory material can be formed by stacking layers of silverhalide material dispersed in a polymer with layers of silver halide freematerial. Alternatively, relatively thick layers of silver halidematerial can be used to form a three dimensional material.

The invention includes a two laser system for the two photon writing ofinformation within a three dimensional optical matrix.

BRIEF DESCRIPTION OF THE DRAWING

FIG. 1 shows a schematic of a two laser system for the writing ofinformation into a three dimensional optical memory.

DETAILED DESCRIPTION OF THE INVENTION

In the known photographic process of image registration, by lightexposure of the silver halide material containing microcrystals of AgHalin the hydrophilic polymer, followed by further development of thelatent photographic image in a water solution of the reducer. Theprocess includes image fixation by dissolving non-irradiated silverhalide therein leaving the exposed silver grains. (T. H. James, “Thetheory of the photographic process”, 4th Ed. MacMillan Publish Co.,N.Y., London, 1977 herein incorporated by reference). Examples of thelight sensitive compounds of the invention include microcrystals ofAgCl, AgCl(Br), AgCl(Br,I), AgBr and AgBr(I). The dimensions of themicrocrystals of AgHal of the invention are in the range of 0.02 to 5μm.

The microcrystals of the invention can be treated with gold and sulfuras well as reduction sensitization processes to increase their lightsensitivity. The spectral sensitization of the silver halidemicrocrystals of the invention by polymethine dyes is used in all rangesof visible and near infra-red light to increase the sensitivity ofsilver halide. The field of spectral sensitivity encompasses the rangefrom about 300 to 1500 nm.

Gelatine or gelatine modified by polymers is used as a hydrophilicpolymer in the invention. The gelatine modified with hydrophilicpolymers can include gelatine modified with polyvinyl alcohol,polyvinylpyrrolidone, polyvinyl sulphate, carboxymethylcellulose,cellulose acetophthalate, phthaloylgelatine or graft polymers ofgelatine with polymethoxydiethyleneglycol acrylate or withpolydiacetoneacrylamide or with poly-N,N′-methylenediacrylamide and canbe used as the hydrophilic polymer of the invention. The photographiclayer is coated over the base, gelatinated, hardened to provide agelatine layer with the necessary physical-mechanical properties anddried. The thickness of the dried photographic layer of the inventioncan be vary from 1 to 100 microns.

The light sensitivity of photo materials of the invention is from about10⁻² to 10⁴ erg/cm² (from 10⁻³ to 10³ of ISO units), and is dependant onthe crystal size. The photo-materials have resolution values of about10² to greater than 10⁴ lines/mm.

The advantages of the silver halide materials of the invention are: highlight sensitivity, high resolution, time stability and mainly thethreshold character of the response to light in the form of a “yes-no”response indicating sufficient or insufficient exposure to light. Eachof the microcrystals of AgHal need to obtain at least four quanta oflight to react. Thus, the quantum sensitivity of the microcrystal has avalue of n≧4. The threshold character of photochemical sensitivity of asingle AgHal microcrystal permits the recording of information by eachmicrocrystal both at the surface and inside the emulsion layer. In otherwords, the threshold value of energy can influence a predeterminedmicrocrystal in the layer. It is possible while exposing the layer toone or two laser beams with an energy at the predetermined point of thelayer above the threshold value of quantum sensitivity of themicrocrystal to influence a predetermined microcrystal.

The main disadvantage of the classic photomaterial is the reading of theinformation by only the integral light absorption on a unit of the area.In other words the information is read by the difference in lightabsorption by the developed film. Because of the nonselective absorptionof light in the visible and infrared ranges by silver imaging, theinformation cannot be read from the depth of the exposed crystal in thephotographic layer, meaning that the information recorded on eachmicrocrystal of the AgHal cannot be read. The other disadvantage of thismaterial is that it has a poor signal-to-noise ratio during the readingprocess. The signal-to-noise is determined by reading the reflectedlight from the film therefore, the contribution to the poorsignal-to-noise ratio by light scattering is significant.

The present invention is directed towards optical recording materialswith luminescent reading overcoming the disadvantages of the knownoptical recording materials and the classical silver halidephotomaterials. Such materials provide increased recording density, anincreased ratio of signal-to-noise and stability of information whilestoring and reading the material. Moreover, such materials provide therecording and reading of information by using light sources withdifferent wavelengths, including infrared wavelengths not only in2-dimensional, but also in 3-dimensional space. This is achieved byusing silver halide material with high resolution ability (2,400 or morelines/mm), and with higher light sensitivity and with a wider region ofspectral sensitivity from 300 to 1000 nm than known optical memorymaterials with luminescent reading. The further treatment and Agtransformation to the image to give particles luminescing in thespectral range from 400-850 nm, provides a great increase in the readingefficiency. Moreover, a variant of the process is possible wherein theunexposed matrix is luminescent and where the matrix has been exposed tolight there is no luminescence. Methods of photographic emulsionsythesis, chemical and spectral sensitization, stabilization, hardening,and chemicophotographic treatment are described in the monograph by T.H. James The Theory of the Photographic Process, 4th Edition, MacMillanPublishing Co. N.Y., London (1977) herein incorporated by reference.

For information recording, the transparent fine-grain silver halideemulsions are used with the microcrystal particle size being less then0.2 microns, preferably 0.08-0.03 microns and with the silver halides ofAgCl, AgCl(Br), AgCl(Br,I), AgBr, or AgBr(I) being suitable. Thephotographic emulsions are obtained by the method of two flowingcontrolled emulsification in the hydrophilic film forming polymer. Asthe hydrophilic polymer, a gelatine or its polymer modification,polyvinyl alcohol and others can be used.

The microcrystals of AgHal can be subjected to chemical sensitization bycompounds containing labile sulfur (for example, Na₂S₂O₃, thiourea), thegold compounds (such as, HAuCl₄, AuCNS and others), and also reductioncompounds such as, SnCl₂, dioxide of thiourea and borohydrides. Thephotographic emulsions can be stabilized by organic stabilizers, such as4-hydroxy-6-methyl-1,3,3a,7-tetraazaindene,1-phenyl-5-mercaptotetrazole, 2-mercapto-5-nitro-benzimadazole, thesodium or potassium salts of 2-mercapto-5-sulphobenzoxazole,2-mercaptobenzothiazole, 2-mercaptobenzoxazole and thiadiazole. Thephotographic emulsions are subjected to the spectral sensitization bypolymethine dyes (cyanine dyes) in the range of visible and near-infra-red spectrum as represented by the general chemical formula (A)

where in the case of the benzothiazole derivatives (X,Y=S); benzoxazolederivative (X,Y=O); benzimidazole derivative (X,Y=NR); quinolinederivative (X,Y=—CH=CH—); indolenine derivative (X,Y=C(R₂)) and so on.For the non-symmetrical dyes X does not equal Y (X≠Y), for example, X=O,and Y=S and are independently selected. Wherein, for each derivative R₂and R₃ are independently selected from H, CH₃, —OCH₃, —SCH₃, —N(CH₃),—N(Et)₂, —N(propyl)₂, —N(iso-propyl)₂, —N(butyl)₂, —N(iso-butyl)₂,—N(sec-butyl)₂, —NCO(CH₂)_(k)H wherein k is 1 to 5, F, Cl, Br, I, —CN,—CO₂H, —CO₂(CH₂)_(j)CH₃ where j is 0 to 4, —CONH₂, —CF₃, SOCF₃, SO₂CF₃,—C₆H₅, and benzyl; n is 0, 1 or 2 and m is 0 or 1; when n is 0 and m is1 then R₆ is independently selected from H, CH₃, C₂H₅, C₆H₅, —NH₂,—NHCOCH₃, —OCH₃, CO₂CH₃; when n is 1 and m is 1 then R₄ and R₆ are H andR₅H, CH₃, C₂H₅. NHCOCH₃, when R₄ and R₆ are linked together and R₄ andR₆ are —(CH₂)₂—, —(CH₂)₃—, or —CH₂C(CH₃)₂CH₂— then R₅ is H, Cl, andC₆H₅; when n is 2 and m is 1 then R₄, R₅ and R₆ are H or R₄ and R₆ are Hand R₅ and R₅ is linked together and R₅ is —(CH₂)₃—, —CH₂C(CH₃)₂CH₂—;and when R and R₁ are independently selected from alkyl then Z⁻ is ananion and when R and R₁ are independently selected from —(CH₂)₃SO₃ thenZ⁺ is a cation. Additionally, the merocyanines and merocyaninocyaninesand others can be used.

The layers are treated with inorganic hardeners (potassium alum orchrome-potassium alum) or with the traditional organic hardeners fromthe class of aldehydes, derivatives of triazoles, oxiranes, vinylsulfonyl derivatives and others.

Photographic layers are subjected to development and fixation afterexposure to light. Formed image consisting of particles of Ag, oxidizedand converted into the colorless or weakly colored insoluble salts withsolubility products less then 10⁻⁸, preferably less than 10⁻¹⁰moles/liter at 25° C. As insoluble salts, AgSCN, AgCN, AgI, Ag₂Cr₂O₇,Ag₂WO₄, Ag₄ [Fe(CN₆)] are used. For this purpose the inorganic solublesalts comprising anions of SCN CN⁻, I⁻, Cr₂O²⁻ ₇, WO²⁻ ₄, [Fe(CN₆)]⁴⁻and others are added to a bleaching vessel containing an oxidizer suchas, K₃[Fe(CN₆)], salts of Fe³⁺, Cu²⁺, quinones and others. The silveroxidation can be conducted with the present of organic acids or theirsalts, for example, oxalates or citrates of the alkaline metals, and thebenzotriazoles 1-mercapto-5-phenyl triazole,2-mercapto-5-nitrobenzamidazole, 2-mercapto-5-sulphobenzoxazole as therespective sodium or potassium salts, to obtain insoluble silver salts.The silver of an image can be transformed in a subsequent process to aninsoluble salt that does not contain silver ions for exampleZn₂[Fe(CN₆)], Cd₂[Fe(CN₆)], ZnS, Cds, BaSO₄ and others.

The three basic methods can be used for the obtaining luminescentparticles in the layer:

1. Adsorption of the luminescent dyes on the insoluble silver or othercationic salts:

2. Preliminary adsorption of polyvalent cations such as, Zn²⁺, Cd²⁺,Sr²⁺, Ni²⁺, Co²⁺, Fe³⁺, Cr³⁺, In³⁺, Bi³⁺, La³⁺, Gd³⁺, V⁴⁺, Cl⁴⁺, Th⁴⁺,and others on the silver salts or other insoluble salts, with thefurther adsorption of the dyes leading to the formation of luminescentmetal-complex compounds.

3. Adsorption of luminescent dyes onto the silver salts or otherinsoluble salts, comprising a mercapto- or benzotriazolyl groupspromoting the adsorption of the dye onto the silver or other insolublesalts. Alternatively, preliminary adsorption of polyvalent anions suchas [Fe(CN)₆]⁻⁴, WO₄ ⁻², MoO₄ ⁻² and others, followed by treatment withmercapto-compounds or benzotriazole to promote the adsorption of theluminescent dyes with some dyes may be preferred.

Alternatively, optical memory devices wherein the matrix is luminescentand the silver particles are doped with multiply charged cations such asCu⁺², Mn⁺² and others can also be prepared. The silver particles aredoped by the adsorption of the multiply charged cations onto the silverparticles. The doped silver particle then suppress the luminescence ofthe luminescent dyes in the matrix adjacent to the particle.

For light sensitive mediums, vacuum sublimated silver halide can beused, which is then subjected to the same treatment as the emulsionlayers of AgHal. The silver halide emulsion can also be applied inlayers to obtain a multi-layered material.

The luminescent compounds can be selected from the following organicdyes described in Krasovitsky, B. M.; Bolotin, B. M. OrganicLuminophores Moscow: Chimia 1984, 336p (Russian); K. Venkataraman, TheChemistry of Synthetic Dyes New York: Academic Press Inc. 1952, Vol. 2both references herein incorporated by refernce.

1. The xanthene dyes of the eoscin type including eosins, fluoresceins,erythrosins, and dichlorofluorescein of general structure I.

wherein R is independently selected from H, Cl, Br, I, NO₂, alkyl andothers; R₁ is H, Na, K, Alkyl; R₂ is independently selected from H, Cl,NH₂, Br, I, isocyanate, isothiocyanate, alkyl anf others; and R₃ isindependently selected from H, Cl, Br, I, NO₂, NH_(2,) alkyl and others.

2. The xanthene dyes of the rhodamine type including the rhodamines B,3B, C, G, 6G, 101, 123 and others having the general structure II.

wherein R is H, CH₃, C₂H₅, CH₂COOH, C₂H₄OH and others; R₁ is H, Na, K,CH₃, C₂H₅, Ar, Alkyl and others; R₂ is independently selected from H,Cl, Br, I, NO₂, alkyl and others, R₃ is independently selected from H,Cl, Br, I, NO₂, isothiocyanate, isocyanate, amines and others and X isan anion selected from Cl⁻, Br⁻, I⁻, ClO₄ ⁻and others.

3. The acridine dyes, including aurazine, trypaflovine,ethoxydiaminoacridine lactate and others of general structure III.

wherein R is H, CH₃, C₂H₅, and others; R₁ is H, C₆H₅, CO₂H and others;R₂ is H, CH₂CH₂OH, alkyl and others; R₃ is independently selected fromH, CH₃, alkyl and others; and X is a anion of F, Cl, Br, I, HCOO⁻,CH₃CHOHCOO⁻, ClO₄ ⁻ and others.

4. The oxazine dyes, including the oxazines 1, 4, 9, 17, 118, nile blue,capry blue A and others having the general structure IVa and IVb:

where R is selected from H, CH₃, and others; R₁ is independentlyselected from H, CH₃, CH₃CH₂ alkyl and others and X is an anion selectedfrom F, Cl, Br, I, ClO₄ ⁻, sulfates, phosphates and others.

5. The azine dyes, including magdala red, lactoflavine of generalstructure V:

wherein R is phenyl, naphthyl; R₁ is H, alkyl, C₆H₅, and others; R₂ isH, alkyl, benzyl, O-benzyl; R₃is H, SO₃H and others; and X is an anion.

6. The indigo dyes, in the form of indigozoles, of general structure VI:

wherein, Y is NH, S and R is independently selected from H, Cl, Br,O-alkyl, NO₂, sulfate, alkyl and others.

7. The polycyclic vat dyes, including aminoanthropyrimidines,anthropyridones, oxa- and tiadiazoloaminoantroquinones, dyes from thegroup of benzanthrones in the form of sulfuric esters of leuco compoundsof general structure VII-XI:

where R is H, NH—C₆H₅, R₁ is H, NHCOAr

where R is H, alkyl, or aromatic

where R is H, C₆H₁₁, C₂H₅, C₂H₄OH.

where R is H, Ar, —SO₂Ar and others.

where R is independently selected from H, Cl, Br, OH, the structure:

and others.

8. The dyes which are forming both the luminescent and non-luminescentcomplexes with polyvalent metal ions, selected from thehydroxyantraquinone derivatives: calcein, calcein blue, xanthocomplexan,methylcalcein, methylcalcein blue as shown in general structuresXII-XVII.

Where R is CH₃, CH₂COOH

9. The cyanine dyes of general structure XVIII.

wherein n is 1,2,3; R is H, SO₃H and others; R₁ is alkyl, (CH₂)_(m)SO₃Hand others m is 3,4 or 5 and X is a anion.

Multi-layer material for use in a three-dimensional memory can beprepared by stacking single silver halide layers on transparent, silverhalide free layers with a thickness of 20-30 microns. Preferably, thethree dimensional, multi-layered material can be prepared by thefollowing extrusion process. The process comprises simultaneouslyextruding from a multi-slit filler relatively thick layers of at leastone of the hydrophilic polymers previously discussed without silverhalide between relatively thin layers of a hydrophilic polymer withsilver halide to obtain a multi-layer structure of alternating layers ofsilver less and silver halide containing material. The number of layerscan be varied from two to twenty or more. The thickness of the layers ofhydrophilic polymer without silver halide can be varied from about 15 toabout 30 microns, preferably about 20 to about 30 microns and thethickness of the layer with silver halide can range from about 0.75 toabout 5 microns, preferably about 1.0 to about 1.5 microns. The silverhalide material of the different layers can be spectrally sensitized todifferent parts of the visible and infra-red spectrum and the recordingof information can then occur through the use of a mask with selectivelight filters. In an analogous manner, the non-silver halide gelatinelayers can contain dyes that are matched or mismatched with thespectrally sensitized silver halide so as to allow the writing ofinformation in the silver halide layers by the use of diode or otherlasers.

A method of producing a multi-layered optical memory material consistsof producing a silver halide one-layered material by pouring the silverhalide emulsion layer with thickness 0.5-1.0 micron on a base selectedfrom cellulose acetates, polycarbonate, or polyethyleneterephthalatewith thickness 20-40 microns, recording optical information thereon,further photochemical treatment and silver image transformation intoimage luminescing in the spectral range from 400 to 850 nm. Forobtaining multi-layered materials the one-layered materials aresequentially glued one to other so that the active silver halideemulsion layers alternate with the inactive separating polymeric layerswhich are transparent for a reading laser beam and the resultingluminescent light. Such material can contain two or more silver halidelayers. Information reading is carried out by detection of theluminescent light irradiated, when a reading laser beam is focused onthe active layers in the points containing luminescent dye.

For the purpose of recording three dimensional information by twosources of light, for example by the recording device shown in FIG. 1, amulti-layer material with silver halide layers having the same activitycan be used. The silver halide layers of multi-layer materials can alsobe spectrally sensitized with polymethine dyes to different wavelengthsof visible or infra-red light. Filter dyes can also be introduced intothe silver halide layers or interlayers for providing color filtration.Such layers can have information recorded on them by printing throughcolor separated masks as is well known in the printing industry. Themulti-layer materials, after exposure to light, are developed andtreated similarly to the monolayer materials.

Another method of producing a multi-layered optical memory deviceconsists of the extrusion of a multi-layer system on a moving polymerfilm with thickness 150-300 microns. The process comprises simultaneousextruding from a multi-slit filler relatively thin (0.5-1.5 microns)layers of hydrophilic polymer with silver halide and between theselayers, relatively thick (20-30 microns) layers of hydrophilic polymerwithout silver halide to obtain a structure of alternating silver halidecontaining (active) and silver halide less (inactive) layers. The numberof the active layers can be two or more.

The following examples are provided in order to further illustrate theinvention but should not be construed as limiting the scope thereof.

EXAMPLE 1 The Synthesis of the AgBr-emulsion.

The synthesis of the super fine grain emulsion of AgBr was conducted bytwo flow emulsification method at a pAg of 2.3 (ie at silverconcentration of [Ag⁺]=10⁻²³ moles per liter) at 40° C. in an apparatuswith a 1.5 liter capacity. The velocity of the supply solutions of AgNO₃(1M) and KBr (1M) was about 3×10⁻⁷ g-mol/sec cm³. The concentration ofthe inert gelatin was 50 g/liter and the mixing up velocity was 1,200rotation/min. The average size of the AgBr microcrystals was about0.05-0.055 microns. The silver content of the emulsion was 16 g/liter.The emulsion was washed in running saltless water at 10° C. for 30 min.The liquid AgBr emulsion then had pyrocatachol (0.1 g/l) and coatadditives such as surfactants, glycerine and thimol and hardeners suchas chromium acetate were added. The viscosity of the emulsion before thecoating of the base was 5.3 centipoise at 40° C. The emulsion was coatedupon gelatine laid glass to obtain a 1.5 g/m² surface concentration ofsilver and transparent layers were obtained. Photoplates were exposed bya FSR-41 sensitometer at a color temperature of 5900° C. of the lightsource. Exposed photoplates were developed with the developer D-19 for 5minutes at 20° C. The plates were fixed in the hardening fixative F-10for 5 minutes, washed with water and dried. The prepared photoplates hadthe following characteristics:

1. The light sensitivity by the darkening density criterion of 0.85above the density of the fog is equal to 4×10⁻² units ISO;

2. The resolution was 4000 lines per millimeter;

3. The contrast coefficient was 9.0;

4. The maximum density of darkening was over 3.0

5. The density of fog was 0.02; and

6. The region of spectral sensitivity was from 300 to 460 nm.

note to Dr. Agranov: WHAT IS DEVELOPER D-19 AND FIXATIVE F-10? ARE THESETRADENAMES OR FORMULAS?

EXAMPLE 2 The Synthesis of the AgBr(I)-emulsion.

The super fine grain emulsion of AgBr(I) (0.7% mol. AgI) was synthesizedby the two flow controlled emulsification method at pAg of 2.3 at 40°C., similarly to Example 1 but the mixture of the KBr and KI solutionwas added to the AgNO₃ solution. The silver content of the emulsionafter being washed was 15 g/liter, and the concentration of gelatin was3.0% by weight. The average size of the microcrystals was 0.03 to 0.04microns. Photoplates were prepared, exposed and treated in the samemanner as the photoplates of Example 1. The photoplates had thefollowing caracteristics:

1. The light sensitivity of 6×10⁻² units ISO;

2. The resolution was 4500 lines per millimeter;

3. The contrast coefficient was 7.0;

4. The maximum density of darkening was over 3.0

5. The density of fog was 0.02; and

6. The region of spectral sensitivity was from 300 to 500 nm.

EXAMPLE 3 The Synthesis of the AgCl-emulsion.

The super fine grain emulsion of AgCl was obtained in a similar manneras Example 1, but instead of KBr, KCl was used. The average size of thecubical microcrystals of AgCl was 0.06 to 0.07 microns. Photoplates wereprepared, exposed and treated in the same manner as the photoplates ofExample 1. The photoplates had the following caracteristics:

1. The light sensitivity of 0.5×10⁻² units ISO;

2. The resolution was 3000 lines per millimeter;

3. The contrast coefficient was 10.0;

4. The maximum density of darkening was over 3.0

5. The density of fog was 0.02; and

6. The region of spectral sensitivity was from 300 to 400 nm.

EXAMPLE 4

To the liquid AgBr-emulsion, synthesized similarly to Example 1, at 40°C., pyrocatechol (0.1 g/liter), the disodium salt of4,4′-bis-(4,6-diphenoxy-1,3,5-triazinyl-2-amino)-stilbene-2,2′-disulfonicacid (1 g/liter), and3,3′-diethyl-6,7,6′,7′-dibenzo-11-methyl-tiatricarbocyanineiodide as analcohol solution with a concentration of 2×10⁻⁴ mol/mol of AgBr, wereadded. After adding the dye, the concentration of the silver ion wasincreased to pAg of 6.5 by 1M AgNO₃. The coat additives, including asurfactant, glycerin and thymol and a hardener, such as chromiumacetate, were added before coating the base with the emulsion. Theviscosity of the emulsion before coating was 5.3 centipoise at 40° C.The emulsion was coated upon the gelatine layered glass to obtain asilver surface concentration of 1.5 g/m².

Photoplates were exposed by a FSP-41 sensitometer behind a KS-14 lightfilter at a color temperature of 2,850° C. of the light source. Exposedphotoplates were developed in the developer D-19 for 5 minutes at 20° C.degree.

The plates were fixed in the hardening fixative substance F-10 for 5minutes, washed with water and dried.

The following characteristics were obtained:

1. The light sensitivity by the darkening density criterion of 0.85above the density of the “fog” is equal to 4×10⁻² units ISO;

2. The resolution ability of 4000 lines/mm;

3. The contrast factor was 9.0;

4. The maximum density of darkening over 3.0;

5. The density of fog was 0.02 and

6. Maximum of spectral sensitization was 860 nm.

The energy sensitivity was measured by a ESP-73 spectrum sensitometer bythe darkening density criterion of 0.5 at λ=860 nm is equal to 10³erg/cm².

EXAMPLE 5

The procedure was the same as in Example 4, except that the spectralsensitizer 3,3′-diethyl-9,11-(β-methyltrimethylene)thiatricarbocyanineiodide with a concentration of 3×10⁻⁴ mol/mol of AgBr was used. Thephoto sensitivity of the photolayers at the maximum sensitivity of 820nm was equal to 7×10² erg/cm². The resolution ability was 4,000lines/mm.

EXAMPLE 6

The procedure used was the same as in Example 4, except that thespectral sensitizer3,3′-diethyl-9,11-(β,β¹-dimethytrimethylen)tiatetracarbocyanine iodideat a concentration of 1.5×10⁻⁴ mol/mol of AgBr was used. The photosensitivity of the photolayers at the maximum sensitization of 920 nmwas equal to 2.0×10³ erg/cm². The resolution ability was 3500 lines/mm.

EXAMPLE 7

The procedure used was the same as in Example 4, except that thespectral sensitizer 3,3′,9-triethyl-4,5,4′,5′-dibenzothiacarbocyaninosylate at concentration of 8×10⁻⁴ mol/mol of AgBr was used. Insteadof the disodium salt of4,4′-bis-(4,6-diphenoxy-1,3,5-triazinyl-2-amino)-stilbene-2,2′ disulfoacid, the 1,10-decamethylene-α-picoline dibromide at a concentration of8×10⁻⁴ mol/mol of AgBr was used. The photo sensitivity of thephotolayers at the maximum sensitivity at 680 nm was 500 erg/cm².

EXAMPLE 8

The procedure the same as in Example 7, except that the sensitizer, thepyridine salt of3,3¹-di-sulfopropyl-5,5¹-diphenyl-9-ethyloxacarbocyanine withconcentration of 10⁻³ mol/mol to AgBr was used. The photo sensitivity ofphotolayers at the maximum of sensitivity at 545 nm was 300 erg/cm².

EXAMPLE 9

The same as in Example 7, except that the sensitizer, the pyridine saltof 3,3¹-di-sulfopropyl-4,5 benzo-5¹-methoxythiamonomethinecyanine withconcentration of 8 10⁻⁴ mol/mol to AgBr is used. The photo sensitivityat the maximum of sensitivity at 475 nm is 800 erg/cm².

EXAMPLE 10

The same as in Example 4, except that the AgCl emulsion is used. Thephoto sensitivity at the maximum of sensitivity at 850 nm is 3,000erg/cm². The resolution ability is 3,000 lines/mm.

EXAMPLE 11

The silver images which was obtained on the samples made as in theExamples 2-10, is bleached at 0.1 M water solution of K₃ [Fe(CN)₆]. Thephotolayers were washed with water, treated with 0.005% eritrosinesolution and washed with water once more. The absorbed dye luminesces inthe green region of the spectrum (max. abs. 547 nm., max. lum. 575 nm.)

EXAMPLE 12

The same as in Example 11, except that in the capacity of theluminescent dye, the 0.015% water solution of the fluorescein is used.The absorbed dye is luminescing in the green range of spectrum.

EXAMPLE 13

The same as in Example b 11, except that in the bleached solution thebenzotriazole is used. The Rodamine 101 is used as the luminescent dye.The absorbed dye is luminescing in the orange-yellow range of spectrum(max. abs. 560 nm, max. lum. 575 nm).

EXAMPLE 14

The silver images on the samples obtained in Examples 2-10 were bleachedin 0.1 M aqueous solution of K₃[Fe(CN)₆], washed with water, treatedwith 0.3M aqueous solution of CdBr₂, washed with water, treated with a2.0M aqueous solution of KCNS, than washed again with water and adsorbederitrosine on formed Cd₂[Fe(CN)₆] from a 0.005% aqueous solution. Theadsorbed dye is luminescent in green region of spectrum (absorbtionλmax.545 nm, luminescence λmax 575 nm).

EXAMPLE 15

The same as in Example 14, except that after treatment with watersolution of KCNS and washing with water, the samples are treated with0.4M aqueous solution of Na₂S_(x)·H₂O, washed with water. The CdSparticle then were treated with Rhodamin B in a 0.005% aqueous solution.The adsorbed dye was luminescent in the orange-yellow range of thespectrum (absorption λmax. 562 nm, luminescence λmax. 585 nm).

EXAMPLE 16

The same as Example 11, except that after bleaching in 0.1M solution ofK₃[Fe(CN)₆] and washing with water, the samples were treated with a 2.0%water-alcohol (1:1) solution of 1-phenyl-5-mercaptotetrazole, washedwith water and adsorbed on formed the silver salt of1-phenyl-5-mercaptotetrazole triethylammonium salt of3,3′-disulfopropyl-5,5′-dichloro-9-ethyloxacarbocyaninebetaine from1.0×10⁻⁵M solution. Adsorbed dye has adsorption λmax. 545 nm andluminescence λmax 580 nm.

EXAMPLE 17

The same as in Example 16, except that a 2.0% water-alcohol (1:1)solution 2-mercaptobenzoxazole was used and the pyridine salt of3,3′-disulfopropyl-5,5′-dimethoxy-9-ethylthiacarbocyaninebetaine, wasadsorbed on the formed silver salt of 2-mercaptobenzoxazole from1.0×10⁻⁵M solution. Adsorbed dye has absorption λmax. 650 nm, andluminescence λmax. 665 nm.

EXAMPLE 18

The same as in Example 16, except that a 2.0% water-alcohol (1:1)solution of 2-mercaptobenzimidazole was used and the potassium salt of1,1,1′,1′-tetramethyl-3,3′-disulfopropylindodicarbocyanine from1.0×10⁻⁵M water solution was adsorbed on the formed Ag-salt of2-mercaptobenzimidazole. Adsorbed dye has absorption λmax. 645 nm andluminescence λmax. 702 nm.

EXAMPLE 19

The same as in Example 16, except that a 2.0% water-alcohol solution of2-mercaptobenzothiazol was used and1,1,1′,1′,3,3′-hexamethylindocarbocyanineiodide was adsorbed from a1.0×10⁻⁵M water alcohol (1:1) solution on formed silver salt of2-mercaptobenzothyazole. The places where there are particles withadsorbed salt do not luminesce and there was luminescence from the bulkpolymer. The dye has an absorption λmax. 650 nm and luminescence λmax.682 nm.

EXAMPLE 20

The same as in Example 11, except that after bleaching, the layer wastreated with 0.1% solution of Ga(NO₃)₃ washed with water and treatedwith 0.05% solution of 8-oxiquinoline. The dye was adsorbed on theinsoluble salts that were located at the places were the photolayer wasexposed to light. The adsorbed dye was luminescing in the yellow-greenrange of spectrum.

EXAMPLE 21

The same as in the Example 20, except that after bleaching, the exposedphotolayer was treated with 0.1% solution of Cu(NO₃)₃ washed with waterand treated with 0.2% water solution of methylcalcein. In the placeswhere the photolayer was exposed to light and the copper salt hadabsorbed the dye had a yellow-green luminescence and the background wasnot luminescent.

EXAMPLE 22

Similarly to the Example 1, the AgBr emulsion was prepared and wasdivided into three parts. The first part of the emulsion was spectrallysensitized as in Example 4, the second part of the emulsion wasspectrally sensitized as in Example 7 and the third one, as in Example8. The sensitized emulsions were coated using a multi-slit filler bylayers on to the gelatine coated polyethylene terephthalate base. Forthe information recording the photomaterial consistently exposed throughthe mask following the light filters, transmitting light with awavelenghth of 860 nm, 680 nm and 545 nm. The photolayers were subjectedto the photo-chemical treatment as in the Example 18 and with a 0.001%water solution of the sodium salt of1,1¹-di-γ-sulfopropyl-5,5¹-disulfo-3,3,3¹,3¹-tetramethylindodicarbocyaninebetaine.The luminescence maximum of the absorbed dye was 700 nm.

EXAMPLE 23

The same as in the Example 22, except that the treatment of layers wasconducted with 0.001% water solution of trisodium salt of1,1′-di-γ-sulfopropyl 5,5′-disulfo-3,3,3′,3′-tetramethyl-n-indotricarbocyaninebetaine. The maximum of luminescence-790 nm.

EXAMPLE 24

The silver halide systems are characterized of high photostability. Theirradiation of the film obtained in Example 22, for 200 hours in acuvett of a Shimadzu spectrofluorimeter at a wavelength of 640 nm usedfor fluorescent excitability did not lead to any changes in thefluorescent intensity. During similar film irradiation, based on thebis-dianilinochloromethyl-1,3,4-oxadiazole as in the U.S. Pat. No.3,869,363, a decrease of the fluorescent intensitivity of 2.5 times wasobserved.

Although certain presently preferred embodiments of the presentinvention have been specifically described herein, it will be apparentto those skilled in the art to which the invention pertains thatvariations and modifications of the various embodiments shown anddescribed herein may be made without departing from the spirit and scopeof the invention. Accordingly, it is intended that the invention belimited only to the extent required by the appended claims and theapplicable rules of law.

1. A digital optical memory device comprising: (a) a digital opticalmemory medium comprising a plurality of layers of a luminescent materialfor an optical digital memory device, each of said plurality of layerscomprising insoluble microparticles dispersed in a water solublepolymer, said microparticles having a particle size less than 0.2microns, said microparticles having a sorbed luminescent dye, saidinsoluble microparticles comprising silver microparticles and insolublemetal salts, said silver microparticles being a product of oxidation ofsilver; and (b) a two-laser system for two photon writing data indigital form on said digital optical memory medium.
 2. The device ofclaim 1, wherein the luminescent dye is selected from the groupconsisting of xanthene dyes, acridine dyes, oxazine dyes, indigo dyes,polycyclic vat dyes, benzanthrones in the form of sulfuric esters ofleuco compounds, dyes form both luminescent and non-luminescentcomplexes with polyvalent metal ions, and cyanine dyes.
 3. The device ofclaim 1 wherein the microcrystals have a size of about 0.02 to 0.08microns and wherein the water soluble polymer is selected from the groupconsisting of polyvinyl alcohol, polyvinyl pyrrolidone, gelatin, gelatinmodified with polyvinyl alcohol, polyvinyl pyrrolidone, polyvinylsulphate, carboxymethylcellulose, cellulose acetophthalate,phthaloylgelatine or graft polymers of gelatin withpolymethoxydiethyleneglycol acrylate, polydiacetoneacrylamide orpoly-N,N′-methylenediacrylamide, and mixtures thereof.
 4. The device ofclaim 1, wherein the silver microparticles are oxidized by an oxidizerselected from the group consisting of K₃[Fe(CN)₆], (NH₄)₂S₂O₈, KMnO₄,CuCl₂, FeCl₃ and quinones, and said oxidation being carried out in apresence of anions selected from the group consisting of SCN⁻, CN⁻,Cr₂O₇ ²⁻, WO₄ ²⁻-, [FeCN)_(6]) ⁻³, oxalate, citrate and anions of1-phenyl-5-mercaptotetrazole, 2-mercapto-bezothiazole,2-mercaptobenzoxazole, 2-mercaptobenzimidazole and organic mercaptocompounds.
 5. A digital optical memory device comprising: (a) a digitaloptical memory medium comprising a plurality of layers of a luminescentmaterial for an optical digital memory device, each of said plurality oflayers comprising insoluble microparticles dispersed in a water solublepolymer, said microparticles having a particle size less than 0.2microns, said microparticles having a sorbed luminescent dye, saidinsoluble microparticles comprising silver microparticles and insolublemetal salts, said silver microparticles being a product of oxidation ofsilver by an oxidizer selected from the group consisting of K3[Fe(CN)6],(NH4)₂S₂O₈, KMnO₄, CuCl₂, FeCl₃ and quinones, and said oxidation beingcarried out in a presence of anions selected from the group consistingof SCN⁻, CN⁻, Cr₂O₇ ²⁻, WO₄ ²⁻, [FeCN)₆]⁻³, oxalate, citrate and anionsof 1-phenyl-5-mercaptotetrazole, 2-mercapto-bezothiazole,2-mercaptobenzoxazole, 2-mercaptobenzimidazole and organic mercaptocompounds; and (b) a two-laser system for two photon writing data indigital form on said digital optical memory medium.
 6. The memory deviceof claim 5, wherein the two-laser system comprises means for two-photonwriting of the data in a three dimensional optical matrix in saiddigital optical memory medium.
 7. The memory device of claim 5 whereinat least one of said plurality of layers has data stored in digital formtherein; and the device further comprises means for reading said data insaid digital form from said digital optical memory medium.
 8. The deviceof claim 5, wherein the luminescent dye is selected from the groupconsisting of xanthene dyes, acridine dyes, oxazine dyes, indigo dyes,polycyclic vat dyes, benzanthrones in the form of sulfuric esters ofleuco compounds, dyes form both luminescent and non-luminescentcomplexes with polyvalent metal ions, and cyanine dyes.
 9. The device ofclaim 5 wherein the microcrystals have a size of about 0.02 to 0.08microns and wherein the water soluble polymer is selected from the groupconsisting of polyvinyl alcohol, polyvinyl pyrrolidone, gelatin, gelatinmodified with polyvinyl alcohol, polyvinyl pyrrolidone, polyvinylsulphate, carboxymethylcellulose, cellulose acetophthalate,phthaloylgelatine or graft polymers of gelatin withpolymethoxydiethyleneglycol acrylate, polydiacetoneacrylamide orpoly-N,N′-methylenediacrylamide, and mixtures thereof.
 10. A method ofreading digital data comprising: (a) providing a digital optical memorymedium, the medium comprising a plurality of layers of a luminescentmaterial for an optical digital memory device, each of said plurality oflayers comprising insoluble microparticles dispersed in a water solublepolymer, said microparticles having a particle size less than 0.2microns, said microparticles having a sorbed luminescent dye, saidinsoluble microparticles comprising silver microparticles and insolublemetal salts, said silver microparticles being a product of oxidation ofsilver, at least one of said plurality of layers having data stored indigital form therein from a two-laser system for two photon writing ofsuch data in digital form on said digital optical memory medium; and (b)reading said data in said digital form from said digital optical memorymedium.
 11. The method of claim 10, wherein the luminescent dye isselected from the group consisting of xanthene dyes, acridine dyes,oxazine dyes, indigo dyes, polycyclic vat dyes, benzanthrones in theform of sulfuric esters of leuco compounds, dyes form both luminescentand non-luminescent complexes with polyvalent metal ions, and cyaninedyes.
 12. The method of claim 10 wherein the microcrystals have a sizeof about 0.02 to 0.08 microns and wherein the water soluble polymer isselected from the group consisting of polyvinyl alcohol, polyvinylpyrrolidone, gelatin, gelatin modified with polyvinyl alcohol, polyvinylpyrrolidone, polyvinyl sulphate, carboxymethylcellulose, celluloseacetophthalate, phthaloylgelatine or graft polymers of gelatin withpolymethoxydiethyleneglycol acrylate, polydiacetoneacrylamide orpoly-N,N′-methylenediacrylamide, and mixtures thereof.
 13. The method ofclaim 10, wherein the silver microparticles are oxidized by an oxidizerselected from the group consisting of K₃[Fe(CN)₆], (NH₄)₂S₂O₈, KMnO₄,CuCl₂, FeCl₃ and quinones, and said oxidation being carried out in apresence of anions selected from the group consisting of SCN⁻, CN⁻,Cr₂O₇ ²⁻, WO₄ ²⁻-, [FeCN)₆]⁻³, oxalate, citrate and anions of1-phenyl-5-mercaptotetrazole, 2-mercapto-bezothiazole,2-mercaptobenzoxazole, 2-mercaptobenzimidazole and organic mercaptocompounds.
 14. A method of storing information on a digital opticalmemory medium, the method comprising: forming a digital optical memorymedium by: simultaneously extruding, from a multi-slit filler, thinlayers of photographic emulsion and between them thick layers of silverhalide free polymer to a substrate to form a multi-layer material;exposing said multi-layer material to light; developing and fixation ofsaid multi-layer material to form silver particles from the exposedsilver halide; oxidation of the silver particles to form the insolublesalt particles; treating the multi-layer material with luminescing dyeand allowing the luminescing dye to be sorbed onto the particles; andwriting data in digital form onto said medium a two-laser system for twophoton writing of such data in digital form on said digital opticalmemory medium.
 15. The method of claim 14, wherein the luminescent dyeis selected from the group consisting of xanthene dyes, acridine dyes,oxazine dyes, indigo dyes, polycyclic vat dyes, benzanthrones in theform of sulfuric esters of leuco compounds, dyes form both luminescentand non-luminescent complexes with polyvalent metal ions, and cyaninedyes.
 16. The method of claim 14 wherein the microcrystals have a sizeof about 0.02 to 0.08 microns and wherein the water soluble polymer isselected from the group consisting of polyvinyl alcohol, polyvinylpyrrolidone, gelatin, gelatin modified with polyvinyl alcohol, polyvinylpyrrolidone, polyvinyl sulphate, carboxymethylcellulose, celluloseacetophthalate, phthaloylgelatine or graft polymers of gelatin withpolymethoxydiethyleneglycol acrylate, polydiacetoneacrylamide orpoly-N,N′-methylenediacrylamide and mixtures thereof.
 17. The method ofclaim 14, wherein the silver microparticles are oxidized by an oxidizerselected from the group consisting of K₃[Fe(CN)₆], (NH₄)₂S₂O₈, KMnO₄,CuCl₂, FeCl₃ and quinones, and said oxidation being canied out in apresence of anions selected from the group consisting of SCN⁻, CN⁻,Cr₂O₇ ²⁻, WO₄ ²⁻-, [FeCN)₆]⁻³, oxalate, citrate and anions of1-phenyl-5-mercaptotetrazole, 2-mercapto-bezothiazole,2-mercaptobenzoxazole, 2-mercaptobenzimidazole and organic mercaptocompounds.
 18. A method of digitally storing information, the methodcomprising: providing one or a plurality of layers comprising silverhalide particles having a particle size less than about 0.2 microns;exposing at least one layer to light using two laser beams at at leastone predetermined point of the layer(s); developing and fixation of saidexposed layer(s) to form silver particles from the exposed silverhalide; oxidizing the silver particles to form insoluble salt particles;and treating the layer(s) with luminescing dye and allowing theluminescing dye to be sorbed onto the particles.
 19. The method of claim18, wherein the luminescent dye is selected from the group consisting ofxanthene dyes, acridine dyes, oxazine dyes, indigo dyes, polycyclic vatdyes, benzanthrones in the form of sulfuric esters of leuco compounds,dyes form both luminescent and non-luminescent complexes with polyvalentmetal ions, and cyanine dyes.
 20. The method of claim 18 wherein themicrocrystals have a size of about 0.02 to 0.08 microns and wherein thewater soluble polymer is selected from the group consisting of polyvinylalcohol, polyvinyl pyrrolidone, gelatin, gelatin modified with polyvinylalcohol, polyvinyl pyrrolidone, polyvinyl sulphate,carboxymethylcellulose, cellulose acetophthalate, phthaloylgelatine orgraft polymers of gelatin with polymethoxydiethyleneglycol acrylate,polydiacetoneacrylamide or poly-N,N′-methylenediacrylamide, and mixturesthereof.
 21. The method of claim 18, wherein the silver microparticlesare oxidized by an oxidizer selected from the group consisting ofK₃[Fe(CN)₆], (NH₄)₂S₂O₈, KMnO₄, CuCl₂, FeCl₃ and quinones, and saidoxidation being carried out in a presence of anions selected from thegroup consisting of SCN⁻, CN⁻, Cr₂O₇ ²⁻, WO₄ ²⁻-, [FeCN)₆]⁻³, oxalate,citrate and anions of 1-phenyl-5-mercaptotetrazole,2-mercapto-bezothiazole, 2-mercaptobenzoxazole, 2-mercaptobenzimidazoleand organic mercapto compounds.